| 1 | """CodeContext - Extension to display the block context above the edit window
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| 2 |
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| 3 | Once code has scrolled off the top of a window, it can be difficult to
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| 4 | determine which block you are in. This extension implements a pane at the top
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| 5 | of each IDLE edit window which provides block structure hints. These hints are
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| 6 | the lines which contain the block opening keywords, e.g. 'if', for the
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| 7 | enclosing block. The number of hint lines is determined by the numlines
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| 8 | variable in the CodeContext section of config-extensions.def. Lines which do
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| 9 | not open blocks are not shown in the context hints pane.
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| 10 |
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| 11 | """
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| 12 | import Tkinter
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| 13 | from Tkconstants import TOP, LEFT, X, W, SUNKEN
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| 14 | import re
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| 15 | from sys import maxint as INFINITY
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| 16 | from idlelib.configHandler import idleConf
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| 17 |
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| 18 | BLOCKOPENERS = set(["class", "def", "elif", "else", "except", "finally", "for",
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| 19 | "if", "try", "while", "with"])
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| 20 | UPDATEINTERVAL = 100 # millisec
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| 21 | FONTUPDATEINTERVAL = 1000 # millisec
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| 22 |
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| 23 | getspacesfirstword =\
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| 24 | lambda s, c=re.compile(r"^(\s*)(\w*)"): c.match(s).groups()
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| 25 |
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| 26 | class CodeContext:
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| 27 | menudefs = [('options', [('!Code Conte_xt', '<<toggle-code-context>>')])]
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| 28 | context_depth = idleConf.GetOption("extensions", "CodeContext",
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| 29 | "numlines", type="int", default=3)
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| 30 | bgcolor = idleConf.GetOption("extensions", "CodeContext",
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| 31 | "bgcolor", type="str", default="LightGray")
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| 32 | fgcolor = idleConf.GetOption("extensions", "CodeContext",
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| 33 | "fgcolor", type="str", default="Black")
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| 34 | def __init__(self, editwin):
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| 35 | self.editwin = editwin
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| 36 | self.text = editwin.text
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| 37 | self.textfont = self.text["font"]
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| 38 | self.label = None
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| 39 | # self.info is a list of (line number, indent level, line text, block
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| 40 | # keyword) tuples providing the block structure associated with
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| 41 | # self.topvisible (the linenumber of the line displayed at the top of
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| 42 | # the edit window). self.info[0] is initialized as a 'dummy' line which
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| 43 | # starts the toplevel 'block' of the module.
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| 44 | self.info = [(0, -1, "", False)]
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| 45 | self.topvisible = 1
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| 46 | visible = idleConf.GetOption("extensions", "CodeContext",
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| 47 | "visible", type="bool", default=False)
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| 48 | if visible:
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| 49 | self.toggle_code_context_event()
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| 50 | self.editwin.setvar('<<toggle-code-context>>', True)
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| 51 | # Start two update cycles, one for context lines, one for font changes.
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| 52 | self.text.after(UPDATEINTERVAL, self.timer_event)
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| 53 | self.text.after(FONTUPDATEINTERVAL, self.font_timer_event)
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| 54 |
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| 55 | def toggle_code_context_event(self, event=None):
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| 56 | if not self.label:
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| 57 | # Calculate the border width and horizontal padding required to
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| 58 | # align the context with the text in the main Text widget.
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| 59 | #
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| 60 | # All values are passed through int(str(<value>)), since some
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| 61 | # values may be pixel objects, which can't simply be added to ints.
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| 62 | widgets = self.editwin.text, self.editwin.text_frame
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| 63 | # Calculate the required vertical padding
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| 64 | padx = 0
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| 65 | for widget in widgets:
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| 66 | padx += int(str( widget.pack_info()['padx'] ))
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| 67 | padx += int(str( widget.cget('padx') ))
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| 68 | # Calculate the required border width
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| 69 | border = 0
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| 70 | for widget in widgets:
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| 71 | border += int(str( widget.cget('border') ))
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| 72 | self.label = Tkinter.Label(self.editwin.top,
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| 73 | text="\n" * (self.context_depth - 1),
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| 74 | anchor=W, justify=LEFT,
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| 75 | font=self.textfont,
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| 76 | bg=self.bgcolor, fg=self.fgcolor,
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| 77 | width=1, #don't request more than we get
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| 78 | padx=padx, border=border,
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| 79 | relief=SUNKEN)
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| 80 | # Pack the label widget before and above the text_frame widget,
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| 81 | # thus ensuring that it will appear directly above text_frame
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| 82 | self.label.pack(side=TOP, fill=X, expand=False,
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| 83 | before=self.editwin.text_frame)
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| 84 | else:
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| 85 | self.label.destroy()
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| 86 | self.label = None
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| 87 | idleConf.SetOption("extensions", "CodeContext", "visible",
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| 88 | str(self.label is not None))
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| 89 | idleConf.SaveUserCfgFiles()
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| 90 |
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| 91 | def get_line_info(self, linenum):
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| 92 | """Get the line indent value, text, and any block start keyword
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| 93 |
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| 94 | If the line does not start a block, the keyword value is False.
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| 95 | The indentation of empty lines (or comment lines) is INFINITY.
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| 96 |
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| 97 | """
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| 98 | text = self.text.get("%d.0" % linenum, "%d.end" % linenum)
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| 99 | spaces, firstword = getspacesfirstword(text)
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| 100 | opener = firstword in BLOCKOPENERS and firstword
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| 101 | if len(text) == len(spaces) or text[len(spaces)] == '#':
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| 102 | indent = INFINITY
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| 103 | else:
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| 104 | indent = len(spaces)
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| 105 | return indent, text, opener
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| 106 |
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| 107 | def get_context(self, new_topvisible, stopline=1, stopindent=0):
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| 108 | """Get context lines, starting at new_topvisible and working backwards.
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| 109 |
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| 110 | Stop when stopline or stopindent is reached. Return a tuple of context
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| 111 | data and the indent level at the top of the region inspected.
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| 112 |
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| 113 | """
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| 114 | assert stopline > 0
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| 115 | lines = []
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| 116 | # The indentation level we are currently in:
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| 117 | lastindent = INFINITY
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| 118 | # For a line to be interesting, it must begin with a block opening
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| 119 | # keyword, and have less indentation than lastindent.
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| 120 | for linenum in xrange(new_topvisible, stopline-1, -1):
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| 121 | indent, text, opener = self.get_line_info(linenum)
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| 122 | if indent < lastindent:
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| 123 | lastindent = indent
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| 124 | if opener in ("else", "elif"):
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| 125 | # We also show the if statement
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| 126 | lastindent += 1
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| 127 | if opener and linenum < new_topvisible and indent >= stopindent:
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| 128 | lines.append((linenum, indent, text, opener))
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| 129 | if lastindent <= stopindent:
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| 130 | break
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| 131 | lines.reverse()
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| 132 | return lines, lastindent
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| 133 |
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| 134 | def update_code_context(self):
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| 135 | """Update context information and lines visible in the context pane.
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| 136 |
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| 137 | """
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| 138 | new_topvisible = int(self.text.index("@0,0").split('.')[0])
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| 139 | if self.topvisible == new_topvisible: # haven't scrolled
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| 140 | return
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| 141 | if self.topvisible < new_topvisible: # scroll down
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| 142 | lines, lastindent = self.get_context(new_topvisible,
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| 143 | self.topvisible)
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| 144 | # retain only context info applicable to the region
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| 145 | # between topvisible and new_topvisible:
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| 146 | while self.info[-1][1] >= lastindent:
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| 147 | del self.info[-1]
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| 148 | elif self.topvisible > new_topvisible: # scroll up
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| 149 | stopindent = self.info[-1][1] + 1
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| 150 | # retain only context info associated
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| 151 | # with lines above new_topvisible:
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| 152 | while self.info[-1][0] >= new_topvisible:
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| 153 | stopindent = self.info[-1][1]
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| 154 | del self.info[-1]
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| 155 | lines, lastindent = self.get_context(new_topvisible,
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| 156 | self.info[-1][0]+1,
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| 157 | stopindent)
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| 158 | self.info.extend(lines)
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| 159 | self.topvisible = new_topvisible
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| 160 | # empty lines in context pane:
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| 161 | context_strings = [""] * max(0, self.context_depth - len(self.info))
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| 162 | # followed by the context hint lines:
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| 163 | context_strings += [x[2] for x in self.info[-self.context_depth:]]
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| 164 | self.label["text"] = '\n'.join(context_strings)
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| 165 |
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| 166 | def timer_event(self):
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| 167 | if self.label:
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| 168 | self.update_code_context()
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| 169 | self.text.after(UPDATEINTERVAL, self.timer_event)
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| 170 |
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| 171 | def font_timer_event(self):
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| 172 | newtextfont = self.text["font"]
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| 173 | if self.label and newtextfont != self.textfont:
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| 174 | self.textfont = newtextfont
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| 175 | self.label["font"] = self.textfont
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| 176 | self.text.after(FONTUPDATEINTERVAL, self.font_timer_event)
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